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Pedro Figueiredo, George P. Nassis and João Brito

/h), sprints (>19.8 km/h), number of accelerations, number of decelerations, dynamic stress load (total of weighted impacts), and total load (total of accelerometer-derived forces applied on the player without any weightings). Magnitude-based inference statistics were used to compare measures over the 3 days

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Heidi R. Thornton, Jace A. Delaney, Grant M. Duthie and Ben J. Dascombe

During the same training camp, 9 a research abstract showed that an increased acceleration/deceleration load (SumAccDec) was associated with very likely small increases in sleep duration (effect size [ES] = 0.27; ±0.16), time in bed (TIB; ES = 0.25; ±0.16), and sleep-onset latency (ES = 0.20; ±0

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Sarah G. Sanders, Elizabeth Yakes Jimenez, Natalie H. Cole, Alena Kuhlemeier, Grace L. McCauley, M. Lee Van Horn and Alberta S. Kong

physical activity (MVPA) on all 7 days in the past week (2013 Youth Risk Behavior Surveillance System). 4 Accelerometers, small electronic devices that measure gravitational accelerations that occur with movement, provide device-based measures of free-living MVPA. In a nationally representative sample of

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Jairo H. Migueles, Alex V. Rowlands, Florian Huber, Séverine Sabia and Vincent T. van Hees

science, and thanks to technological evolution towards smaller, cheaper, and power efficient sensors, accelerometers now tend to store ‘raw’ data for offline processing and analysis. The data recorded are typically expressed in gravitational acceleration ( g ) because this is the reference point for

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Niels J. Nedergaard, Mark A. Robinson, Elena Eusterwiemann, Barry Drust, Paulo J. Lisboa and Jos Vanrenterghem

Purpose:

To investigate the relationship between whole-body accelerations and body-worn accelerometry during team-sport movements.

Methods:

Twenty male team-sport players performed forward running and anticipated 45° and 90° side-cuts at approach speeds of 2, 3, 4, and 5 m/s. Whole-body center-of-mass (CoM) accelerations were determined from ground-reaction forces collected from 1 foot–ground contact, and segmental accelerations were measured from a commercial GPS accelerometer unit on the upper trunk. Three higher-specification accelerometers were also positioned on the GPS unit, the dorsal aspect of the pelvis, and the shaft of the tibia. Associations between mechanical load variables (peak acceleration, loading rate, and impulse) calculated from both CoM accelerations and segmental accelerations were explored using regression analysis. In addition, 1-dimensional statistical parametric mapping (SPM) was used to explore the relationships between peak segmental accelerations and CoM-acceleration profiles during the whole foot–ground contact.

Results:

A weak relationship was observed for the investigated mechanical load variables regardless of accelerometer location and task (R 2 values across accelerometer locations and tasks: peak acceleration .08–.55, loading rate .27–.59, and impulse .02–.59). Segmental accelerations generally overestimated whole-body mechanical load. SPM analysis showed that peak segmental accelerations were mostly related to CoM accelerations during the first 40–50% of contact phase.

Conclusions:

While body-worn accelerometry correlates to whole-body loading in team-sport movements and can reveal useful estimates concerning loading, these correlations are not strong. Body-worn accelerometry should therefore be used with caution to monitor whole-body mechanical loading in the field.

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Theresa L. Miyashita and Paul A. Ullucci

variables were derived from data collected via GForceTracker sensors (GFT; GForceTracker ™ , Markham, ON) and included average linear acceleration, head injury criteria (HICs), Gadd severity index, rotational resultants, and total number of head impacts. Participants A total of 33 Division I Men’s lacrosse

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Saud F. Alsubaie, Susan L. Whitney, Joseph M. Furman, Gregory F. Marchetti, Kathleen H. Sienko and Patrick J. Sparto

Technologies BV, Enschede, The Netherlands) 17 , 18 was mounted on each subject’s posterior lower back at the level of the iliac crest (L4). The IMU measured trunk angular displacement and velocity in the pitch and roll planes, and linear acceleration in the antero–posterior (A/P) and mediolateral (M

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Kai Yan Lui, Patricia Hewston and Nandini Deshpande

demonstrated increased lower limb strength does not independently improve the speed of STS performance in older adults ( Schlicht, Camaione, & Owen, 2001 ). During STS, the otolith organs in the vestibular system may be highly stimulated in response to the horizontal and vertical linear acceleration of the

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Paul G. Montgomery and Brendan D. Maloney

(direction) data were collected as per unit specifications for the accumulation of jumps in low (<20 cm), medium (20–40 cm), and high bands (>40 cm); high-speed change of direction for right and left (>3.5 m·s −1 ); accelerations and decelerations in low (<2.5 m·s −1 ), medium (2.5–3.5 m·s −1 ), and high

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Adriana M. Holmes and David M. Andrews

The purpose of this research was to examine the effects of voluntarily manipulating muscle activation and localized muscle fatigue on tibial response parameters, including peak tibial acceleration, time to peak tibial acceleration, and the acceleration slope, measured at the knee during unshod heel impacts. A human pendulum delivered consistent impacts to 15 female and 15 male subjects. The tibialis anterior and lateral gastrocnemius were examined using electromyography, thus allowing voluntary contraction to various activation states (baseline, 15%, 30%, 45%, and 60% of the maximum activation state) and assessing localized muscle fatigue. A skin-mounted uniaxial accelerometer, preloaded medial to the tibial tuberosity, allowed tibial response parameter determination. There were significant decreases in peak acceleration during tibialis anterior fatigue, compared to baseline and all other activation states. In females, increased time to peak acceleration and decreased acceleration slope occurred during fatigue compared to 30% and 45%, and compared to 15% through 60% of the maximum activation state, respectively. Slight peak acceleration and acceleration slope increases, and decreased time to peak acceleration as activation state increased during tibialis anterior testing, were noted. When examining the lateral gastrocnemius, the time to peak acceleration was significantly higher across gender in the middle activation states than at the baseline and fatigue states. The acceleration slope decreased at all activation states above baseline in females, and decreased at 60% of the maximum activation state in males compared to the baseline and fatigue states. Findings agree with localized muscle fatigue literature, suggesting that with fatigue there is decreased impact transmission, which may protect the leg. The relative effects of leg stiffness and ankle angle on tibial response need to be verified.